Re: [PATCH] netfilter: use per-cpu spinlock rather than RCU (v2)

Eric Dumazet
2009-04-14T19:30:54Z

Stephen Hemminger a écrit :
> Subject: iptables:
>
> This is an alternative version of ip/ip6/arp tables locking using
> per-cpu locks. This avoids the overhead of synchronize_net() during
> update but still removes the expensive rwlock in earlier versions.
>
> The idea for this came from an earlier version done by Eric Duzamet.
> Locking is done per-cpu, the fast path locks on the current cpu
> and updates counters. The slow case involves acquiring the locks on
> all cpu's.
>
> The mutex that was added for 2.6.30 in xt_table is unnecessary since
> there already is a mutex for xt[af].mutex that is held.
>
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> ---
> include/linux/netfilter/x_tables.h | 5 -
> net/ipv4/netfilter/arp_tables.c | 112 +++++++++------------------------
> net/ipv4/netfilter/ip_tables.c | 123 +++++++++++--------------------------
> net/ipv6/netfilter/ip6_tables.c | 119 +++++++++++------------------------
> net/netfilter/x_tables.c | 28 --------
> 5 files changed, 110 insertions(+), 277 deletions(-)

Oh well, it seems factorization of this stuff is not what you want, so
I'll stop arguing.

Please check spelling of my name in ChangeLog, and more importantly :
initialize arp_tables_lock that is missing in V1/2

for_each_possible_cpu(cpu)
spin_lock_init(&per_cpu(arp_tables_lock, cpu));

Then please add my :

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>

Thanks